1. The Field of the Invention
The present invention relates generally to a pour nozzle for a waste treatment system, and more particularly, to a pour nozzle having a substantially arch-shaped portion, for use with a plasma arc centrifugal treatment system.
2. Description of the Prior Art
The plasma arc centrifugal treatment (PACT) system uses refractory compounds in insulation and containment applications because the PACT system uses a plasma torch as a primary heat source where temperatures in the primary melt chamber of the PACT system may range from 2000 degrees Fahrenheit (1094 degrees Celsius) to 3800 degrees Fahrenheit (2094 degrees Celsius). Refractories are ceramic materials commonly used in the manufacture of metals, glass, chemicals, petroleum products, and the destruction of hazardous and non-hazardous wastes. These materials serve as insulation or containment materials that withstand the harsh, high temperature and corrosive environments of many industrial processes. Refractories are typically composed of silica, alumina, chrome oxide, magnesia, dolomite, graphite, or combinations of these materials.
Materials are fed into the PACT system, melted in the centrifuge, and poured through an orifice, located on the axis of the centrifuge, defined within a nozzle. The pour nozzle can be water-cooled copper or made of ceramic materials. Types of ceramic materials used have included silicon carbide, light-weight porous cement-bonded alumina refractory, alumina rammable and chrome oxide alumina rammable refractory, magnesia-carbon resin-bonded refractory brick, and compression molded clay-bonded coarse grain alumina-chrome oxide refractory. Typically, the pour orifice is either a cylinder or a tapered frustum of a cone that acts as a channel for directing molten material from the centrifuge into a slag mold as can be seen in FIGS. 1, 2.
The nozzle forms a transition point between the molten flowable material and its discharge into a slag mold. When the material consists of a molten inorganic material, it is a viscous fluid that passes through the pour nozzle coating the nozzle walls. The cylindrical portion of long pour nozzles tends to promote slag build-up and throat closure. If this occurs, the plasma torch is brought into a position to impinge the plasma stream on the plugged orifice of the nozzle. When the nozzle consists of a ceramic material, the extreme heat of the plasma stream may rapidly erode the nozzle and decrease its operational life. Thus, it can be seen that the cylindrical and tapered ceramic nozzle designs are usually high maintenance items causing a significant amount of down-time for plant operations.